The change in passive membrane polarization of cells, axons, and dendrites beneath a cortical surface stimulation electrode has been calculated at a variety of shapes, orientations, and depths. The method of third moment factor analysis described in the last report can now be applied to data with intrinsic variance. Thus it now appears possible to calculate independent linear combinations of empirical signals. BIBLIOGRAPHIC REFERENCE: Marks, W.B. and Loeb, G.E.: Action currents, internodal potentials, and extracellular records of myelinated mammalian nerve fibers derived from node potentials. Biophys. J. 16: 655-668, 1976.